Elusive Secondary Air P0411 Trouble Code

[patroklai]

Hello,

I've been dealing with a SAP issue for nearly 3 years. Albeit, most of that time I left the car parked in the garage and didn't worry about it.

Currently, my car has a Stage 2 evolve tune with Primary cat delete, cold start delete and rev limit removal.

This setup worked fine until after I had some actuator issues and battery issues.

I have since replaced the actuators (problem solved), and replaced the battery with an aftermarket cheaper version I had a local BMW shop (not dealer) do the coding on. I'm not super confident about their work, however, as I also paid for power steering fluid flush and clutch/brake fluid flush/replacement but my pedal feels spongier than ever and the steering wheel sometimes "skips" which leads me to think they such and left a bunch of air in the system.

Anyways- at the time identified the p0411 code, I also got a 2B59 that I was only able to see using the evolve diagnostic software (not my physical code reader).

I paid an arm and a leg to have the thermostat replaced (I have yet to re-check for that code), but the SAP/P0411 continues to be an issue.

The reason I bring the thermostat issue up, is because I found a thread where someone potentially resolved both codes with a new battery (voltage issue). My plan is to check diagnostic codes for the 2B59 and see if it's still present.

Back to the SAP problem, here's what I've done:

Removed SAP
Tested SAP with a 12v battery
SAP spins freely, suctions air on one end and pushes it out the other without issues. The pump does not make any strange noises.
I pulled the salmon/pink relay and tested it using a 12v battery as well as multi meter for continuity. The relay passed with flying colors.

Lastly, I replaced the fuse (it was burnt when this all started). The new 40a fuse has not blow after several restarts and driving the car around for half hour or so. However, the P0411 is now pending and I suspect in a few more drive cycles will come back.

Another interesting observation is that when I started the car with the pump disconnected, I got the same p0411 error right away. When the pump is connected, I didn't get it right away, but after driving the car, it seems to have triggered it.

Another thing I haven't checked (or replaced) is the idle air control sensor. I believe this is the sensor that attaches to one of the hoses that connects the pump to the intake. Some users reported that as a potential issue.

That said, I welcome any experiences or knowledge you all may have on the subject.


What is most troubling for me, is the fact that the startup sequence was disabled via tune (cold start delete), but yet the car somehow still knows to somehow test for the pump and related components.

Lastly, I have not messed with the check valves or rear hose that connects to them. They are very far back in the motor and don't want to deal with it unless it makes sense to troubleshoot that far. At this time, the issue feels to be related to electronics, and not a mechanical problem but that's up for debate.

At one point, I had my tuner include a SAP delete condition to my pre-existing tune but unfortunately, I will not be able to pass emissions with two monitors that never set to ready so I went back to the previous tune that does not disable the SAP (not to be confused with the cold start sequence delete; these are distinct things).

Thanks in advance.

[bmwlover0725]

Is this an issue with clogged ports? If so, I'm an expert at unclogging them without taking apart the engine lol. Let me know. If I forget to respond just PM me.

[patroklai]

Originally Posted by bmwlover0725

Is this an issue with clogged ports? If so, I'm an expert at unclogging them without taking apart the engine lol. Let me know. If I forget to respond just PM me.

Are you talking about the check valves behind the engine? I'm not sure if they are clogged or not. What's your method?

[bmwlover0725]

Originally Posted by patroklai

Are you talking about the check valves behind the engine? I'm not sure if they are clogged or not. What's your method?

Not the check valves, but I'd replace them if you're going to do this job. I replaced mine when I did it for safe measure. They're pretty cheap for an M part.

So this is your problem I think. P0411 is when insufficient flow is detected by the DME. These cars have a common issue (which is why the SAP delete was created for tunes) which causes the ports inside of the head to become clogged with carbon and not allow air to pass through once it enters the engine from the pump and check valves.

Here is what I did to fix mine. I also had a guy recently praise me heavily for this fix lol. I'm actually somewhat proud of it because normally, this requires that the heads be removed from the engine and it becomes an extremely expensive repair. Keep in mind, this could also just be a stuck valve, but I doubt it.

I first put Seafoam each check valve by dumping it in through a hose with the check valve hoses temporarily removed (this can be done with the vehicle assembled, but takes some patience because you'll be doing it by feel). Once I did that, I started the vehicle for a few seconds (cold) to let the pump run and blow the seafoam in through the valves. I then shut off the car and let it sit over night. After this, I removed the intake manifold and pump with the hoses the next day. I then removed the check valves. They're EXTREMELY difficult to get to without removing the exhaust manifold, but it can be done. You'll have to try a combination of sockets and/or open ended wrenches to get a couple of the check valve bolts. With everything removed you'll want to get a wire pipe cleaning brush (Harbor Freight or a home improvement store) and push it in and out of the port where the check valve goes. Do this several times and take your time. You can never go at it too much. Once I did this, I reassembled everything, started the car, reset my codes, and the problem was gone.

[patroklai]

Couple questions:

"I first put Seafoam each check valve by dumping it in through a hose with the check valve hoses temporarily removed"

so you disconnected the upper hose that connects to the back of the pump, and ran a smaller hose to each check valve to fill it up with seafoam? How seafoam would you say to use?

Also - I have a cold start delete as part of my tune.. I don't have this start up sequence and my pump won't start at all. How is the ECU picking up P0411?

Thanks.

[bmwlover0725]

Originally Posted by patroklai

Couple questions:

"I first put Seafoam each check valve by dumping it in through a hose with the check valve hoses temporarily removed"

so you disconnected the upper hose that connects to the back of the pump, and ran a smaller hose to each check valve to fill it up with seafoam? How seafoam would you say to use?

Also - I have a cold start delete as part of my tune.. I don't have this start up sequence and my pump won't start at all. How is the ECU picking up P0411?

Thanks.

Okay so as far as the Seafoam goes, just as much as you can fit until it starts overflowing from the valve. That really isn't much, but it will work alright. Just make sure you only turn on the vehicle for a few seconds. You'll see the smoke coming out as long as the ports aren't completely clogged.

However - as far as your tune goes, I have ZERO idea how it's throwing this code. That's wild! I've never heard of this happening when the system isn't running. I'd contact your tuner. Who did you use?

[patroklai]

Evolve.

Apparently the cold start delete is separate from SAP delete. I have a tune with one and then another with both deleted.

I would assume the pump has other functions besides just the cold start. The code came up after driving for a bit but not after a few restarts.

[bmwlover0725]

Originally Posted by patroklai

Evolve.

Apparently the cold start delete is separate from SAP delete. I have a tune with one and then another with both deleted.

I would assume the pump has other functions besides just the cold start. The code came up after driving for a bit but not after a few restarts.

I wish someone would come in and explain this actually because I had no idea that cold start and SAP delete were two separate things! Very interesting. So yeah it does sound like your ports may be clogged, but now I'm slightly confused.

[patroklai]

Same, lol. Been looking to understand myself.

The cold start delete removes the start up sequence where the SAP is used, but I don't think thats the only scenario the ECU is using/testing the SAP. I think it does it while driving too. That's where the total SAP delete comes in.

Clogged ports make sense to me. Those valves are a PITA to get to so I'm going to swap back to my SAP delete tune and see if I get lucky with a readiness monitor after enough driving. I did hear from one member that it took him 1.5 months of casual driving for the monitor to set.

[bmwlover0725]

Originally Posted by patroklai

Same, lol. Been looking to understand myself.

The cold start delete removes the start up sequence where the SAP is used, but I don't think thats the only scenario the ECU is using/testing the SAP. I think it does it while driving too. That's where the total SAP delete comes in.

Clogged ports make sense to me. Those valves are a PITA to get to so I'm going to swap back to my SAP delete tune and see if I get lucky with a readiness monitor after enough driving. I did hear from one member that it took him 1.5 months of casual driving for the monitor to set.

If you can do that then you'll be fine. I understand monitors and the need to set them. I live in NY where you can only have one not ready. Also, the light would have caused me to fail immediately which is why I opted to fix it.

[patroklai]

It's the same for me. My cat delete monitor will never set to ready but my hope is the SAP will despite the delete based on the feedback of one member.

[BPMSport]

SAP delete involves removing other faults because the SA relay and other components are removed, which would cause additional faults.

[amrazM]

You can disable the cold start sequence but if there is a failed component in the secondary air injection system it will throw a fault.

[patroklai]

Originally Posted by patroklai

It's the same for me. My cat delete monitor will never set to ready but my hope is the SAP will despite the delete based on the feedback of one member.

So I was wrong about this. I'll share some clarity with you all in a moment.

[patroklai]

Over my quest these past several years I've learned this:

Cold start sequence and SA injection are separate funcions.
Cold start delete does not affect the SAP or related components.
The SAP failure seems common in these cars for a number of reasons but carbon buildup seems to be what starts to wear on the components.

SAP delete is real. But all the components needed for SAP must be physically in the car and present. At least the electronics.

I'm at 8/9 readiness and scheduled to test tomorrow afternoon. Good enough for me.

Feel free to PM with me questions. Case closed.

[bmwlover0725]

Originally Posted by patroklai

It's the same for me. My cat delete monitor will never set to ready but my hope is the SAP will despite the delete based on the feedback of one member.

Interesting. My cat monitor takes forever, but eventually sets despite it being a delete. All of my monitors set because I still have secondary air.